close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2122735

код для вставки
Patented July 5, 1938
2,122,735
UNITED STATES PATENT OFFICE
2,122,735
MANUFACTURE OF MANGANESE DIOXIDE
Alfred Félix Sebastien Bellone, Lyon, France, as
signor to Societe des Usines Chimiques Rhone
Poulenc, Paris, France
No Drawing. Application January 10, 1935, Se
rial No. 1,158. In Great Britain January 12,
1934
7 Claims.
The present invention relates to the production
of manganese dioxide by the oxidation of man?
ganese compounds.
According to the Weldon process, it is known
,5; to regenerate manganese dioxide from manga
nese salts by precipitating manganese hydrate
with lime and then oxidizing this hydrate by air
in the presence of an excess of lime, the dioxide
being recovered in the form of calcium man
”
be used, as even a pressure of air amounting
to 1.5 kg. per sq. cm. enables a product to be
obtained in 12 hours in which 76% of the man
ganese in the manganese oxide produced is in
the form of dioxide, but the speed of oxidation
diminishes more and more rapidly as the degree
of oxidation becomes more and more increased.
Such diminution in the rate of oxidation however,
becomes less as the pressure is greater. It is
ganite.
therefore preferable technically to employ great
Meyer and Nerlich (Ztschr. f. anorg. Ch. 1921,
116, p. 118 et seq.) have studied the oxidation of
er; pressures of air or of oxygen, for example,
pressures of 5 to 25 kgs. per sq. cm. in the case of
manganous hydrate in an ammoniacal medium
by air under atmospheric pressure. By ascer
taining the amount of active oxygen in the pre
cipitate obtained, they have con?rmed the re
air; or corresponding oxygen pressures of up to 5
kgs. per sq. cm.
In the practice of my invention I use air or 15
oxygen under such pressure that the partial
sults of the Weldon process in an alkaline earth
medium. . In a soda or potash medium, however,
per sq. cm.
they have found that for concentrated solu
20 tions the results are very variable and correspond
‘
(Cl. 23—145)
to a lower degree of oxidation than that of
MnOz. Furthermore the products contain more
or less combined alkali.
In an ammoniacal me
dium, the precipitate had the composition of
2,5 manganic hydroxide (Mn(OH) a).
I have found that under certain conditions
the oxidation of manganous hydrate in an. am
moniacal medium by means of air or a gas rich
in oxygen can be caused to lead to the precipi
{39 tation of very rich artificial oxide of manganese
with an oxygen content far higher than that
of manganic hydroxide, i. e., containing a large
proportion of manganese dioxide. The necessary
condition for this result is that the pressure of
35 the oxygen should be greater than the partial
pressure of this element in ordinary atmos
pheric air.
The process according. to the present inven
tion, therefore, consists in causing manganous
40 hydrate to react in an ammoniacal medium with
air under pressure or with pure oxygen either
at normal pressure or at increased pressure.
The manganous hydrate in an ammoniacal me
dium to be used according to the present inven
45 tion is most generally obtained by using the re
action product obtained by allowing an excess
10
pressure of the oxygen is greater than 0.30 kg.
It is advantageous to carry out the oxidation
in the presence of certain elements such as
20
copper or chromium, or their derivatives, or of
certain organic bodies such as hydroquinone,
which exert a favourable action on the oxida
tion.
The precipitate obtained by this reaction is an 25
oxidation product of manganese, free from im
purities and containing the manganese chie?y
in the form of manganese dioxide (MnOz) with
a small proportion of manganese oxide (MnO).
This product thus obtained furnishes an arti? 30
cial manganese dioxide which is very active
both for use in oxidation reactions and as a gal
vanic element.
By treatment with a suitable
reagent (as, for example, dilute sulphuric acid),
practically the whole of the manganous oxide
can be dissolved out so as to leave as undis
35
solved residue a practically pure and very active
dioxide.
The following examples, Without being limi
tative, illustrate how the invention may be car
40
ried out in practice:
Example 1.--In a closed apparatus, furnished
with a suitable stirrer, 2 litres of an aqueous so~
lution containing 2 gram molecules of man
ganous sulphate, 2 gram molecules of ammoni
45
um sulphate and 2 grams of copper sulphate, are
of ammonia to react on a manganous salt such
as a chloride or a sulphate obtainedin the acid
treatment of manganese ores. The ammonium
introduced. Into this stirred solution 6 gram
molecules of ammonia are introduced and then
immediately oxygen is introduced at a rate in
salt formed by the reaction does not in any Way
impede the oxidation; it is even advantageous to
proportion to its absorption. At the end of 24 50
hours a precipitate containing all the manganese
introduced is separated; this precipitate con
tains 80% of the manganese in the state of the
dioxide.
Example 2.—In an autoclave capable of be 55
introduce an excess thereof into the reaction
medium.
In order to carry out the invention in practice,
55 relatively weak pressures of air or oxygen can
2
2,122,735
ing stirred or otherwise agitated, are introduced
the partial pressure of the oxygen is greater than
10 litres of an aqueous solution of manganous
0.30 kg. per sq. cm.
sulphate containing 1 gram molecule per litre,
3. A process for the preparation of arti?cial
oxide of manganese containing a large proportion
of manganese dioxide, consisting in oxidizing
manganous hydroxide in an aqueous ammoniacal
and 28 gram molecules of ammonia. 10 grams
of potassium bichromate in aqueous solution are
then added. Oxygen under a pressure of 3 kgs.
per sq. cm. is then introduced into the autoclave
which is stirred for 4 hours.
The precipitate
obtained is separated by simple ?ltration; 90%
10 of the manganese contained in this product is
found to be in the state of dioxide.
Emctmple 3.-—In the same apparatus contain.
ing a similar charge, air isintroduced under a
pressure of 15 kgs. per sq. cm. After stirring for
15 several hours a precipitate is obtained of which
82% of the. manganese is in the state of the di
oxide. By treating this product With dilute sul
phuric acid a practically pure manganese dioxide
is
20
obtained.
-
'
Example 4.—In a closed apparatus, ?tted With
a suitable stirring gear, there are introduced 2
litres of an aqueous solution containing 2 gram
molecules of manganous sulphate and 80 gram
molecules of ammonium sulphate.
Into the -
25 stirred, solution 5.6 gram molecules of ammonia
are introduced and absorbed and then oxygen
is introduced, maintaining a pressure of 1 kg. per
sq. cm. At the end of 24 hours the precipitate
which contains all the manganese which has been
introduced, is separated off.
This precipitate
contains 81% of the manganese in the state of
dioxide.
‘
.
What I claim and desire to secure by Letters
Patent
is:
35
l. A process for the preparation of arti?cial
oxide of manganese containing a large propor
tion of manganese dioxide, consisting in oxidizing
manganous hydroxide in an aqueous ammoniacal
solution by means of one of that group of sub
stances including oxygen in a pure state and
oxygen diluted with an inert gas under such a
solution in which an ammonium salt is also pres
ent by means of one of that group of substances
including oxygen in a pure state and oxygen
diluted with an inert gas under such a pressure 10
that the partial pressure of the oxygen is greater
than 0.30 kg. per sq. cm.
>
4. A process for the preparation of arti?cial
oxide of manganese containing a large proportion
of manganese dioxide, consisting in oxidizing 15
manganous hydroxide in an ammoniacal medium
in which hydroquinone is present, by means of
onev of that group of substances including oxygen
in a pure state and oxygen diluted With an inert
gas under such a pressure that the partial pres 20
sure of the oxygen is greater than that of oxygen
in atmospheric air.
'
'
5. A process for the preparation of arti?cial
oxide of manganese containing a large propor
tion of manganese dioxide. consisting in oxidizing 25
manganous hydroxide in an ammoniacal medium
in which a copper salt is present, by means of
oxygen either’ in the pure state or diluted with
an inert gas under such a pressure that the par
tial pressure of the oxygen is greater than 0.3 kg. 30
per sq. cm.
'
_
6. A process for the preparation of arti?cial
oxide of manganese containing a large proportion
of manganese dioxide consisting in oxidizing
manganous hydroxide in an ammoniacal medium
in which a chromate is present, by means of oxy
gen either in the pure state or diluted with an
inert gas under such a pressure that the partial
pressure of the oxygen is greater than 0.3 kg. per
sq. cm.
'
'7. A process for the preparation of arti?cial
oxide of manganese containing a large proportion
pressure that the partial pressure of the oxygen
is greater than 0.30 kg. per sq. cm.
2. A process for the preparation of arti?cial
oxide of manganese containing a large propor
of manganese diOXideLWhich consists in oxidizing '
manganeze hydroxide in an ammoniacal medium
in the presence of a catalyst of the group con
tion of manganese dioxide, consisting in oxidiz
mate, by means of one of the group comprising
ing the reaction product formed by an excess of
aqueous ammonia solution and a manganese salt
50 by means of one of that group of substances in
cluding oxygen in a pure state and oxygen di
luted with an inert gas under such a pressure that
sisting of hydroquinone, a copper salt and a chro
oxygen in a pure state and oxygen diluted by an
inert gas,_the oxidizing being effected under such
pressure that the partial pressure of the oxygen
is greater than that of oxygen in atmospheric air.
ALFRED FELIX sE'BAsTIEN BELLONE.
Документ
Категория
Без категории
Просмотров
0
Размер файла
280 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа